Shell腳本gradle命令和gradlew命令的區(qū)別

了解gradlew和gradle命令的區(qū)別之前，嘗試花幾分鐘思考下面幾個問題：

  • gradlew是一個什么命令工具呢？
  • 為什么要有這個工具？
  • gradlew腳本是怎樣的？
  • gradlew命令和gradle命令的區(qū)別？

一、gradlew、gradle腳本的區(qū)別

先看看gradlew腳本代碼

#!/usr/bin/env sh

PRG="$0"
# 1.檢查是否是軟連接
while [ -h "$PRG" ] ; do
    ls=`ls -ld "$PRG"`
    link=`expr "$ls" : '.*-> \(.*\)$'`
    if expr "$link" : '/.*' > /dev/null; then
        PRG="$link"
    else
        PRG=`dirname "$PRG"`"/$link"
    fi
done
SAVED="`pwd`"
cd "`dirname \"$PRG\"`/" >/dev/null
APP_HOME="`pwd -P`"
cd "$SAVED" >/dev/null

APP_NAME="Gradle"
APP_BASE_NAME=`basename "$0"`

# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
DEFAULT_JVM_OPTS=""

# Use the maximum available, or set MAX_FD != -1 to use that value.
MAX_FD="maximum"

warn () {
    echo "$*"
}

die () {
    echo
    echo "$*"
    echo
    exit 1
}

# 2.獲取系統(tǒng)內(nèi)核信息
cygwin=false
msys=false
darwin=false
nonstop=false
case "`uname`" in
  CYGWIN* )
    cygwin=true
    ;;
  Darwin* )
    darwin=true
    ;;
  MINGW* )
    msys=true
    ;;
  NONSTOP* )
    nonstop=true
    ;;
esac

# 3.設(shè)置classpath路徑
CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar

# Determine the Java command to use to start the JVM.
if [ -n "$JAVA_HOME" ] ; then
    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
        # IBM's JDK on AIX uses strange locations for the executables
        JAVACMD="$JAVA_HOME/jre/sh/java"
    else
        JAVACMD="$JAVA_HOME/bin/java"
    fi
    if [ ! -x "$JAVACMD" ] ; then
        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME

Please set the JAVA_HOME variable in your environment to match the
location of your Java installation."
    fi
else
    JAVACMD="java"
    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.

Please set the JAVA_HOME variable in your environment to match the
location of your Java installation."
fi

# Increase the maximum file descriptors if we can.
if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
    MAX_FD_LIMIT=`ulimit -H -n`
    if [ $? -eq 0 ] ; then
        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
            MAX_FD="$MAX_FD_LIMIT"
        fi
        ulimit -n $MAX_FD
        if [ $? -ne 0 ] ; then
            warn "Could not set maximum file descriptor limit: $MAX_FD"
        fi
    else
        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
    fi
fi

# For Darwin, add options to specify how the application appears in the dock
if $darwin; then
    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
fi

# For Cygwin, switch paths to Windows format before running java
if $cygwin ; then
    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
    JAVACMD=`cygpath --unix "$JAVACMD"`

    # We build the pattern for arguments to be converted via cygpath
    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
    SEP=""
    for dir in $ROOTDIRSRAW ; do
        ROOTDIRS="$ROOTDIRS$SEP$dir"
        SEP="|"
    done
    OURCYGPATTERN="(^($ROOTDIRS))"
    # Add a user-defined pattern to the cygpath arguments
    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
    fi
    # Now convert the arguments - kludge to limit ourselves to /bin/sh
    i=0
    for arg in "$@" ; do
        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option

        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
        else
            eval `echo args$i`="\"$arg\""
        fi
        i=$((i+1))
    done
    case $i in
        (0) set -- ;;
        (1) set -- "$args0" ;;
        (2) set -- "$args0" "$args1" ;;
        (3) set -- "$args0" "$args1" "$args2" ;;
        (4) set -- "$args0" "$args1" "$args2" "$args3" ;;
        (5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
        (6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
        (7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
        (8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
        (9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
    esac
fi

# Escape application args
save () {
    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
    echo " "
}
APP_ARGS=$(save "$@")

# Collect all arguments for the java command, following the shell quoting and substitution rules
eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"

# by default we should be in the correct project dir, but when run from Finder on Mac, the cwd is wrong
if [ "$(uname)" = "Darwin" ] && [ "$HOME" = "$PWD" ]; then
  cd "$(dirname "$0")"
fi

# 4.執(zhí)行java命令運行wrapper jar包里頭的類文件
exec "$JAVACMD" "$@"

代碼量不多，腳本主要干了幾件事：

獲取電腦系統(tǒng)內(nèi)核的信息，JRE環(huán)境信息等；

設(shè)置classpath路徑；

執(zhí)行java命令工具，調(diào)用gradle jar包的class文件

在gradlew腳本中添加log打?。?/p> 

echo "$JAVACMD $@"

$ ./gradlew -v
/Library/Java/JavaVirtualMachines/jdk1.8.0_172.jdk/Contents/Home/bin/java -Xdock:name=Gradle -Xdock:icon=/Users/cengfanwei/zengfw/ATrain/media/gradle.icns -Dorg.gradle.appname=gradlew -classpath /Users/cengfanwei/zengfw/ATrain/gradle/wrapper/gradle-wrapper.jar org.gradle.wrapper.GradleWrapperMain -v

從打印結(jié)果可知，最終其實是通過java命令執(zhí)行g(shù)radle-wrapper.jar包的GradleWrapperMain類，再繼續(xù)看看GradleWrapperMain干了什么事情...

public class GradleWrapperMain {
    public static final String GRADLE_USER_HOME_OPTION = "g";
    public static final String GRADLE_USER_HOME_DETAILED_OPTION = "gradle-user-home";
    public static final String GRADLE_QUIET_OPTION = "q";
    public static final String GRADLE_QUIET_DETAILED_OPTION = "quiet";

    public static void main(String[] args)
            throws Exception {
        File wrapperJar = wrapperJar();
        File propertiesFile = wrapperProperties(wrapperJar);
        File rootDir = rootDir(wrapperJar);

        CommandLineParser parser = new CommandLineParser();
        parser.allowUnknownOptions();
        parser.option(new String[]{"g", "gradle-user-home"}).hasArgument();
        parser.option(new String[]{"q", "quiet"});

        SystemPropertiesCommandLineConverter converter = new SystemPropertiesCommandLineConverter();
        converter.configure(parser);

        ParsedCommandLine options = parser.parse(args);

        Properties systemProperties = System.getProperties();
        systemProperties.putAll(converter.convert(options, new HashMap()));

        File gradleUserHome = gradleUserHome(options);

        addSystemProperties(gradleUserHome, rootDir);

        Logger logger = logger(options);

        WrapperExecutor wrapperExecutor = WrapperExecutor.forWrapperPropertiesFile(propertiesFile);
        wrapperExecutor.execute(args, new Install(logger, new Download(logger, "gradlew", wrapperVersion()), new PathAssembler(gradleUserHome)), new BootstrapMainStarter());
    }
    
    // ...
}


public class WrapperExecutor {
    // ...
    public void execute(String[] args, Install install, BootstrapMainStarter bootstrapMainStarter) throws Exception {
        File gradleHome = install.createDist(this.config);
        bootstrapMainStarter.start(args, gradleHome);
    }   
    // ...
}

public class BootstrapMainStarter {
    // ...
    public void start(String[] args, File gradleHome) throws Exception {
        File gradleJar = this.findLauncherJar(gradleHome);
        URLClassLoader contextClassLoader = new URLClassLoader(new URL[]{gradleJar.toURI().toURL()}, ClassLoader.getSystemClassLoader().getParent());
        Thread.currentThread().setContextClassLoader(contextClassLoader);
        Class<?> mainClass = contextClassLoader.loadClass("org.gradle.launcher.GradleMain");
        Method mainMethod = mainClass.getMethod("main", String[].class);
        mainMethod.invoke((Object)null, args);
        if (contextClassLoader instanceof Closeable) {
            contextClassLoader.close();
        }
    }   
    // ...
}

public class GradleMain {
    // ...
    public static void main(String[] args) throws Exception {
        (new ProcessBootstrap()).run("org.gradle.launcher.Main", args);
    }
}

public class Main extends EntryPoint {
    // ...
    public static void main(String[] args) {
        (new Main()).run(args);
    }

    protected void doAction(String[] args, ExecutionListener listener) {
        this.createActionFactory().convert(Arrays.asList(args)).execute(listener);
    }

    CommandLineActionFactory createActionFactory() {
        return new CommandLineActionFactory();
    }
}

看到這里比較清晰的，WrapperExecutor會先檢查是否有配置已下載到本地的gradle路徑，沒有則先從服務(wù)器下載（根據(jù)gradle-wrapper.properties文件配置distributionUrl鏈接），再是根據(jù)傳進來的命令行參數(shù)，用命令行工廠構(gòu)建不同的命令行action，并通過命令解析器execute對應(yīng)的命令行action；

Gradle Wrapper工作流程圖

Gradle Wrapper工作流程圖

思考：如何避免同個項目在其他開發(fā)者電腦上運行時，因gradle版本不同而引發(fā)各種問題？

可上傳wrapper目錄，統(tǒng)一gradle-wrapper.properties配置的gradle版本，使得其他開發(fā)者也用同個gradle版本構(gòu)建同個項目。

以上是關(guān)于gradlew腳本的了解，那gradle腳本呢？我們直接打開文件對比，就基本可以知道兩份腳本之間的主要差異了：

差異一
差異二

差異之所以在classpath，是因為java命令運行jar包里頭的文件的話，我們需要通過classpath指定命令運行時查找class文件的路徑。

同樣，在gradle腳本中添加 echo "$JAVACMD $@" 日志打印，得到如下打印：

echo "$JAVACMD $@"

$ ~/Library/Android/gradle/gradle-4.4/bin/gradle -v
/Library/Java/JavaVirtualMachines/jdk1.8.0_172.jdk/Contents/Home/bin/java -Xdock:name=Gradle -Xdock:icon=/Users/cengfanwei/Library/Android/gradle/gradle-4.4/media/gradle.icns -Dorg.gradle.appname=gradle -classpath /Users/cengfanwei/Library/Android/gradle/gradle-4.4/lib/gradle-launcher-4.4.jar org.gradle.launcher.GradleMain -v

你會發(fā)現(xiàn)如果直接通過gradle命令的話，其實運行的是gradle-launcher-4.4.jar包里頭的org.gradle.launcher.GradleMain類，之后的流程就跟上面從GradleMain開始一樣的了！

思考：使用gradle命令效率比使用gradlew效率快的原因？

因為gradlew命令，需要執(zhí)行一些額外流程，如類加載、反射gradle-launcher-xx.jar包里頭的類等等，最后再到org.gradle.launcher.GradleMain類的main函數(shù)。

二、gradle常用命令

前面了解gradlew、gradle的區(qū)別之后，下面列出一些gradle常用的命令

命令 描述
gradle androidDependencies 查看項目依賴樹
gradle assembleDebug 構(gòu)建debug版本apk
gradle assembleRelease 構(gòu)建release版本apk
gradle installDebug 安裝debug版本apk到設(shè)備，在adb設(shè)備時，這個命令省每次都還要敲install命令行
gradle installRelease 同installDebug，只是apk版本是release
gradle uninstallDebug 卸載debug版本apk
gradle clean 清除build緩存
gralde build --stacktrack 構(gòu)建整個模塊，且打印整個構(gòu)建流程的日志（包括異常日志）
?著作權(quán)歸作者所有,轉(zhuǎn)載或內(nèi)容合作請聯(lián)系作者
【社區(qū)內(nèi)容提示】社區(qū)部分內(nèi)容疑似由AI輔助生成，瀏覽時請結(jié)合常識與多方信息審慎甄別。
平臺聲明：文章內(nèi)容（如有圖片或視頻亦包括在內(nèi)）由作者上傳并發(fā)布，文章內(nèi)容僅代表作者本人觀點，簡書系信息發(fā)布平臺，僅提供信息存儲服務(wù)。

相關(guān)閱讀更多精彩內(nèi)容

友情鏈接更多精彩內(nèi)容